High-pressure apparatus



May 29, 1951 T. c. POULTER 2,554,499

HIGH-PRESSURE APPARATUS Filed Sept. 8, 1947 2 Sheets-Sheet 2 l-.EU

20.4 8. 36 jf f3 4a 49 /f l 47 @1 //.r

Patented May 29, 1951 HIGH-PRESSURE APPARATUS Thomas C. Poulter, LaGrange, Ill., assigner to Armour Research Foundation of IllinoisInstitute of Technology, Chicago, Ill., a corporation of IllinoisApplication September 8, 1947, Serial No. 772,645

12 Claims. l

This invention relates to a high pressure apparatus for the obtaining ofvery high pressures, such as those of the order of one million poundsper square inch and over. Such apparatus is frequently referred to as apressure bomb.

Heretofore, for eXtra high pressure work, pressure bombs have often beenconstructed as a tube, simple or composite, open at both ends anddefining a cylindrical bore running axially for the full length of thetube. Cylindrical pistons, one of which may be stationary and the othermovable with respect to the bomb, are arranged for introduction into theopen ends of the bore in opposed position. Pressure is applied eX-ternally and axially to the two pistons as by means of a hydraulic pressor other suitable means, to create the desired pressure within the bombbore between the adjacent ends of the two pistons.

The pistons, as heretofore employed, are usually made of high gradesteel or sintered carbide, tempered glass-hard, and are generallycapable of withstanding pressures greater than those which can besustained by the bomb. The piston strength increases as the unsupportedlength decreases and as the diameter decreases. Values of one-halfmillion pounds per square inch are obtainable with pistons of one-halfinch in diameter and pressures of even a few million pounds per squareinch are attainable with one-eigth to one thirty-second inch diameterpistons. n

In the past, bombs have often been constructed as single thick-walledtubes or a nest of two or more such tubes shrunk or taper-fitted andpressed together. Calculation and control of stresses in such bombs aredifcult. Usually creep is involved, and the permissible pressures whichcan be utilized are empirically determined by the length of time andnumber of repetitions of applied pressure, and by the temperature andnature of contents compressed in the bomb. If the bomb does not burst,often the central bore is stretched and deformed, requiring reboring,grinding, and lapping to a new truly cylindrical form. This is atime-consuming and expensive process. Other limitations and.disadvantages of heretofore constructed bombs are well known to thoseskilled in the art and efforts to overcome them have only been partiallysuccessful.

I have devised an entirely novel and improved bomb construction whichavoids the above mentioned difculties and which has additionaladvantages not heretofore realized. In general, the bomb of my presentinvention comprises a relatively thin-walled inner tubular member deninga working volume to be subjected to high pressure, an outer ring-likemember, and a plurality of sector-shaped blocks in mutual laterallysupporting relationship compressively confined between the inner tubularmember and the outer ring-like member. In the bomb of my invention,extremely high stresses produced near the center are transmittedradially outwardly by essentially pure compression to outer members,including the outer annular ring and the sector-shaped blocks, whichserve to restrain these extremely high stresses with the imposition ofrelatively moderateV stresses upon the outer ring-like member. Theintermediate sector-shaped block elements cannot fail since they aresubjected to practically pure compression with lateral and mutualsupport.

Furthermore, the bomb of my invention can be readily assembled anddisassembled so that the central tubular liner can be removed andreplaced and any other parts readily interchanged. This feature ofconstruction is of particular convenience not only in the replacing ofliners with corroded or worn out bores but also in the accommodation ofliners with different bore diameters and correspondingly sized pistonsas desired. The major components of my bomb seldom or never requirerenewal, a factor which is an obvious advantage.

The construction of my bomb also makes it feasible and convenient tointroduce electrical inlar liner denes the working volume of the bomband such liner can be placed under a predetermined initial radialpressure to absorb a portion of the pressure developed within suchworking volume yof the bomb.

It is a further important object of this invention to provide a highpressure bomb capable of withstanding pressures of the order of over amillion pounds per square inch, and wherein the stresses therein set upnear the center of the bomb are properly controlled and restrained bythe outer members of the bomb construction at relatively moderatestresses.

It is a still further important object of this invention to provide ahigh pressure bomb in which a relatively thin-walled tubular liner isconfined within an outer annular member by means of sector-shaped blocksinitially placed under corn'- pressive stress by said outer annularmember to withstand the pressures radially transmitted out- Wardly.

Other and further important objects of this invention will be apparentfrom the disclosures in the specification and the accompanying drawings.l

On the drawings: v

Figure 1 is a vertical cross-sectional View, with parts shown inelevation, Aof a high pressure apparatus. made in accordance with Amypresent invention, the apparatus being shown as positioned upon thefloor or bed of a hydraulic press between a lower stationary bed and anupper movable ram of the press.

Figure 2 is a partial sectional View taken substantially along the lineII-II of Figure 1.

Figure 3 is a vertical sectional View of a modied form of the innerbom-b construction,

Figure 4 is a broken, vertical sectional view, with parts shown inelevation, of a modified construction of the bomb shown in Figure 1, themodified bomb being adapted for electrical heating of the pressurechamber.

As shown on the drawings: v

The reference numeral I@ (Figs. 1 and 2) indicates generally a highpressure apparatus, or pressure bomb, embodying the principles of myinvention. Said apparatus I includes an inner tubular member, or liner II, which is of relatively thin-walled construction and which is open atboth of its ends for the reception of relatively movable pistons I2 andI3 to be described in greater detail later on. Said pistons I2 and I3serve to produce the desired high pressure in working volume A withinthe bore I4 of the tubular liner II.

A plurality of sector-shaped blocks l5 conne and laterally support thetubular liner I I. When assembled in place about said tubular liner I I,the assembled blocks I5 define an inner cylindrical surface it forconforming contact with the outer cylindrical surface of the tubularliner II. As will be later explained, the outer diameter of the tubularliner II may be of the exact size of the diameter of the innercylindrical surface I6, or it may be undersized or oversized, dependingupon the results desired.

The outer surface of the assembled blocks I5 is preferably slightlytapered, as indicated by the surface Il, to facilitate the mounting ofsaid assembled blocks within an outer, annular retaining member IShaving a similarly tapered inner surface i5. The outer annular retainingmember i8 may be of a solid piece of metal, or alloy, or may be ofcomposite construction. The tapered surfaces I1 and I9 are preferablyconical surfaces of the same small axial taper so as to permit a presst. The sector-shaped blocks I5 are rst assembled about the tubular linerII 4 and the outer annular retaining member I8 then pressed axially ontothe liner-block assembly. In the final assembled relationship, as shownin Figure 1, the blocks I5 are under predeterminedcircumferential-radial compression, as in the case of very thick stavesof a barrel bound together by hoops. With a definitely undersizedtubular liner Il, the sector-shaped blocks I5 alone, by virtue of thekeystone or barrel stave action that results, would support the entirecompressive forces exerted by the outer annular retaining member I8 andno radially compressive force would be exerted on the outer surface 20of the tubular liner II.

On the other hand, if the tubular liner Il were definitely oversized,the entire compressive forces exerted by the outer annular retainingmember I8 would be transmitted to the outer surface 2U of the tubularliner II. Therefore, by a proper 'selection of the outer diameter of thetubular liner Il with respect to the inside diameter vof the cylindricalsurface It defined by the inside ends of the sector-shaped blocks I5, itis possible to control the initial radial compression on the liner IIacross the surface 2S thereof to any 'desired fraction of the totalinitial radial compression'exerted by the outer ring I8.

This is a great advantage since it permits the use of an inner tubularliner I I of a comparatively thin-walled section without crushing of theliner by initial external radial pressure set up upon assembly of theapparatus. The large initial compression produced by the outerrestraining annular member I8 is initially carried largely `by acircumferential pressure between the contacting lateral surfaces 2| `ofthe sector-shaped blocks. As hydrostatic pressure is built up within theworking volume A within the bore I4 of the tubular liner II under theaction of the pistons I2 and I3, this pressure is transmitted radiallyoutwardly, first through the sector-shaped blocks I5 and then to theouter annular retaining member I8. The sector-shaped blocks I5themselves provide mutual lateral support circumferencewise and havelongitudinal and radial dimensions 'both large compared to thecorresponding dimensions cf the high pressure working face Ill. lI"herefore, at 4all times the sector-shaped blocks I5 are stressed invirtually pure compression with adequate lateral support so that theirfailure is virtually impossible. Moreover, the outer annular retainingmember I8 is of a size and accessibility that, without overstressing, itwill readily support any pressure which it is feasible to develop yinthe space A. Consequently, the major outer parts of the bomb such as thesector-shaped blocks I5 and the annular retaining member I8, haveindefinitely Vlong life.

The end faces of `the assembled blocks I5 provide `an outer annularplane surface 22 (Fig. l) and an inwardly directed conical recess 23.The tubular Yliner II 4isof such length as to terminate at the bottomsof said conical recesses 23. A stationary base block '254, supportedupon the floor or bed 25 of a hydraulic press (not shown), extends intoone of said vrecesses 23 and is provided with a conformingly taperedconical end portion 26. Thepiston I3 projects from the end of said baseblock v2d to leave an annular plane shoulder 21 for supporting theadjacent end of the tubular liner lI l. The movable ram, indicated bythe reference'numeral 28 is similarly provided with a conically shapedblock 2e which extends into the corresponding conical recess 23. Thepiston I2 projects from the conical end of block.

29 into the tubular liner IIy in opposed relationship to the piston I3.The end portions of said pistons I2 and I3 are preferably carefullylapped to t exactly the bore I4 of the tubular liner Il.

For some applications, a pressure tight fit between the pistons I2 andI3 and the wall of the bore I4 may be insured by providing seals 30 and3l, respectively, on the ends of said pistons. Said seals may be formedof any suitable plastic or resilient material, such as a soft vulcanizedrubber, either natural or synthetic, a silicone resin, or the like,capable of withstanding the temperatures employed. Said seals 30 and 3|may initially be somewhat oversize to effect a tight seal, and need notbe secured in any manner to the ends of said pistons. These seals 3D and3| are more conveniently merely pushed ahead of the active ends of thepistons I2 and I3.

ln assembling the apparatus, the sector-shaped blocks I5 are firstassembled in place around the tubular liner I I, and the outer annularretaining member I8 is then pressed or shrunk in place about theassembled blocks to clamp the blocks together by virtue of the conicalsurface of contact between the outer surfaces I'i of the blocks I5 andthe inner surface I9 of the member I8. The pistons I2 and I3 areinserted into the ends of the upper block 29 and the lower base block2li, which may be of hard steel or sintered carbide. The lower,stationary piston I3 is inserted into the lower end of the tubular linerI I, and the entire bomb and lower piston assembly placed on the floor25 of a hydraulic press. The desired charge is then placed in the cavityA, the upper piston I2 inserted, and pressure applied by the ram 28 tothe upper block 2S and piston I2.

In the specic form of my apparatus illustrated in Figures 1 and 2, thesector-shaped blocks I5 are shown provided with plane lateral faces andthe dihedral angle between these plane faces exactly S60/n", where n isthe number of sectors around the liner. For optimum control of theextremely high stresses which may be produced in the' central regions 0fthe bomb, it may be desirable to depart from such geometric accuracy andthe opportunity to do so in the bomb of my invention is one of the majoradvantages of the design. It may not be desirable that the lateral facesof the blocks be exactly plane or that the dihedral angles between thelateral faces of the sector blocks be exactly S60/n". Instead of thelateral faces being at, they may be slightly convex, or in general, ofcompound curvature. In such case, after the outer annular member I8 hasbeen pressed over the slightly tapered outer conical surface I9 of theblocks I5, a predetermined circumferential compressive stress can beestablished throughout the sector-shaped blocks, with initial radial andlongitudinal gradation of this circumferential stress pre-controlled asdesired.

Alternatively, the sector-shaped blocks may be machined or ground asgeometrically perfect as feasible, both with respect to dihedral anglesand the flatness of the lateral faces. Before assembly,

however, thin shims of metal foil, ake mica, or

the like, of desired thickness and contour may be inserted between thesector-shaped blocks, and the blocks then assembled and the outerannular member pressed into place. The additional thickness, whencompressed between the blocks, creates additional circumferentialpressure, with kresultant radial and circumferential pressure profilesaccurately predetermined at will. Shims of different thickness andthickness profiles can be ineluded for different bombs or for differentpressure runs of the same bomb, thus making the initial pressuredistribution different, as desired, for different internal liners,operating pressures, and different temperature profiles (with resultantdifferent thermal dilation and distortion which will exist under thedifferent temperature gradients) for particular heating and externalcooling conditions of various tests. Such graded shims, therefore, makepossible the grading of circumferential pressure over the faces of thesector-shaped blocks adjustable at will to compensate for the conditionsof any given pressure run of any bomb.

As a still further essential refinement in the control of stresses inthe crucial central highstress region made possible by the bomb of myinvention, a controlled longitudinal beam action can be introduced intothe block sectors I5. This may be accomplished in either or both of twoways. First, when internal pressure is developed in the working space A(Fig. l), as pressure is applied to the pistons I2 and I3, then, due tothe fact that the axial length of A is much shorter than the length ofthe sectors I5 and outer ring I I3, the stretching or radial dilationlwill be greatest at and near the central plane II-ll. This action maybe accentuated by purposely reducing the thickness of the outer ring I8.at its central section by making its outer surface 52 spool or capstanshaped. Secondly, instead of making the inner surface IS of outer ringI8 and outer surface Il of assembled sectors I5 both truly straightmating conical surfaces, either or both of these surfaces may beintentionally ground with an axially extending concavity to fit tighterat the ends than at the center. ractically, it is convenient to make theinner surface I9 of the outer ring I 8 truly conical and to grind thecuter conical surface Il of the assembled sectors I5 slightly more atthe center than is represented by a true cone.

Using either or both of these expedients in combination, hydrostaticpressure applied in the working volume A will cause the sectors I 5 todilate or bulge radially outward more at their centers than at theirends, i. e., to bend slightly along their length like the lengthwisebend in wooden barrel staves. This will produce nominal tensile stressesaxialwise in the outer wide sections of the blocks I5 where areas arelarge and other stresses comparatively small. However, more important,it will create large axial cornpressive stresses in the narrow innerportions of the block sectors I5 adjacent to liner II, these axialstresses being greatest, in a lengthwise direction, in the regionsurrounding working velume A.

In the preceding exposition, descriptive terms have been used such asblending like barrel staves, etc. It must be realized, however, that alldilations, bending, intended departures from true geometric at surfacesand angles or conical surfaces actually are matters of a few mils atmost either initially or during pressure application and are, therefore,far too small to indicate in the figures.

It is well known that with equal triaxial compressive stresses, i. e.,three equal compressive stresses in mutually orthogonal directions whichis equivalent to hydrostatic pressure, any homogeneous metal canwithstand any hydrostatic pressure whatever, no matter how large,without plastic distortion. Now, although it is not possible to designmy bomb so that/(a) the circumferasl-strot -ential pressure stressesproduced in blocks I by Inon-flat or :slightly off-angled faces or shimsbetween `vfaces, and (b) axial stresses in the inner portions of thesectors I5 due to lengthwise bending Awill, at all times of a pressurecycle from zero to full hydrostatic pressure in space A, both be equalto each other and to (c) the radial pressure exerted by liner II itself,plus the hydrostatic pressure internal to A, yet in the crucial centralregion of the sectors, these three triaxial compressive stresses can becontrolled in my bomb, never to become unequal to a sufficiently largeamount to cause permanent distortion of the sectors I5 or outer ring I8.

As 'internal pressure Vis created in the bomb, the additional radialcompression combines 'With and alters the initial circumferential andaxial bendlingst'resses in such a manner that at 'no time 'and at noplace in the sector-shaped blocks do the resultant combined triaxialstresses cause plastic deformation of the sector blocks I5. This is adistinctly `superior result, made possible by my invention, unobtainableheretofore with the use of the ordinary, thick-Walled tube bombconstruction Where the metal immediately surrounding -the pressurecavity is plastically deformed in Atension each time the tube is loadedand in compression each time the tube is unloaded. Under thoseconditions, a feW repetitions of such cyclic plastic deformations causesfailure after a limited number of times of use. While the thin-Walledinner 'tubular liner I I of my bomb may, of course, be plasticallyldeformed upon application and release of pressure, it can be made of asofter alloy which is capable of appreciable deformation, since thestresses which it is called upon to With- Stand are nominal, just likean inner tube in a tire casing. Indeed, for some applications, I nd itdesirable to replace liner II by a soft rubber tube (or the like) closedat both ends and containing the charge to be compressed. In this case,pistons l2 and I3 (Fig. l), are made to ac'- 'curately nt the innercylindrical surface i3 ofthe sector blocks I5, which pistons thenlongitudinally compress such soft rubber or metal capsule together Withits contents.

Moreover, the high unit radial stresses at the central ends of thesector-shaped blocks are fanned out and become nominal pressures at theinside surface I8 of the outer annular member I8. Since the annularmember I8 is of comparatively large inside diameter, the ratio of itsouter to inner radii is not far from unity. Therefore, the metal intheouter annular member I3 is nearly uniformly stressed over itscross-section in hoop tension, so that the required cross-section neednot be excessive, nor the alloy used in making the member I3 so criticalas with usual high pressure bomb constructions.

External radial support for the tubular liner I in the construction ofFigures l and 2 is adequate under all circumstances. Because of thethin-walled section of the liner and the friction along the Surface 28,axial support of the liner may not be required under ordinarycircumstances. However, should the liner Wall be comparatively thickandthe temperature and pressure of operation extreme, there is apossibility that the tubular liner I I may be squeezed in two parts nearits center by internal hydrostatic pressure and the two parts extrudedaxially endwise out of the bomb.

lIn order to prevent this possibility, the alternative constructionVillustrated in Figure 3 -maybe employed. As there shown, the innertubular liner IIav is .provided with an outer circumferentially -utedsurface 32. The uting may be helically arranged, in a manner similar tothreads on a screw, or may be arranged annularly. The inner surfaces ofthe blocks I5 are similarly contoured as at 33. This arrangementeiectively prevents failure `of the liner by extrusion. There -isadequate axial strength in the sector-shaped blocks I5 to rprovide this`additional function of longitudinal-or axial support Vfor the tubularliner vIlor IIa.

One great advantage of the bomb of my ing vention is the conveniencewith which it .may be modified v'for electrical heating of the'chargewlhile such charge is under extreme pressure. vA vpreferred embodimentof this modication is shown in Figure 4.

InvFgure 4, similar reference numerals are used to indicate the tubularliner II, the sectorshaped blocks I5 and the outer annular retainingmembernl'. The upper piston I2 is mounted as previously described in ablock 28, but an electrically conductive plate 35 is positioned in placeagainst the top of said yblock 29 and a layer of insulation 36 insertedbetween said plate 35 and the upper movable ram 28.

The lower piston 3l is made of slightly less diameter than the inside ofthe tubular liner II to permit a thin tube, or .sleeve 38, formed ofmica or other suitable insulating material, vto fit snugly around thepiston 31 and extend upward- 4ly from the block I39 'into the tubularliner II. Said insulating sleeve 38 extends from the end surface of theblock 39 to a point somewhat short of the Working end o'f the piston I2in its initial position.

An Vinsulating washer M! lies against the end of said block 39 about the,piston 3l and insulating sleeve 38.Y This insulating Washer i6 preventsthe conical face of block 39 from completely seating in the conicalrecess 23 in the ends of segments I5, the conical air gap so formedelectrically insulating Athe respective members from each other, Aplate4I of electrically conductive material is inserted lbetween the block 33and a yplate 42 of insulating material that rests upon the filoor -2'5of the hydraulic press. The electricallyconductive plates 35 and il areprovided with contacts 4'3 .and M, respectively, for connecton vvithalsource of electrical current including Wires 45 and 4,5. In addition, anelectrical contact, including an electrically conductive plate 'II-'landi-a contact post 48, may be provided for the outer annular ring I8,with a Wire 49 forconnection to the source of electrical current inparallel With or as an .alternative to wire 45.

In assembling .the apparatus illustrated .in Figures, thepiston 31 issecured in the end ofthe block A39 andthe insulating sleeve 38 slippedover the projecting end of the piston. The insulating Washer 40 is theninserted `in vplace against the endof .the block 39. The entiresub-assembly including the `piston 3l, block 39, insulating sleeve 38and insulating vWasher d0 may then be chilled, if desired, and theinsulating sleeve 38 and piston 31 inserted into the end of the .tubularliner II, the latter `having been heated just -`prior-to such insertion.

By :careful selection of dimensions, such as the diameters of the partsand the thickness ofthe insulating sleeve 38, and by proper choice ofassembly temperature of parts, the thermalshrink t :may be :made to.stronglycompress the insulating sleeve 38 between the stationarypiston31 .and the lower end of the tubular liner II. Pressure is still furtherincreased by the external compression on the liner II produced by thesectorshaped blocks I and the outer annular member I 8, which are nextassembled in place in that order. The upper edge of the lower piston 31and the lower internal edge of the tubular liner II may be slightlyrounded off to prevent cutting through the insulating sleeve 38 underthe conditions of extreme radial compression to which the sleeve issubjected.

The active charge is next inserted in the cavity provided by the linerII and insulating sleeve 38. If the charge is electricallynon-conductive, or it may be desirable to do so for other reasons, itmay be enclosed in a thin-walled metal capsule 50. Said capsule 55 maybe closed at both ends and formed with such thin walls and of suitablemetal so as to be easily collapsible. The capsule :dts snugly inside ofthe insulating sleeve 33 to rest against the end of the piston 31, butextends about one diameter beyond the end of the sleeve 38 toward thepiston I2. When the upper movable piston I2 is inserted into the tubularliner II and pressure is applied, the piston will cause the upper end ofthe capsule 50 to collapse, or mushroom, and make electrical contactwith the tubular liner II along the end cylindrical surface thereof, asindicated at 5I.

Electrical contact with the capsule 50 is made at each end by thepistons I2 and 31. (Elastic fluid seals 333 and 3l of Figure 1 areomitted, or, if included in Figure 4, the lower one 3l at least must bemade of electrical conducting material.) If the charge itself iselectrically conductive, the

metallic capsule 50 may be omitted, in which case, the charge itselfmakes electrical contact with the ends of the pistons I2 and 31 and withthe exposed inner surface of the tubular liner I I at 5 I.

The bomb and piston assembly is insulated from the floor and from theram 28 by means of the plates or sheets 42 and 36 of insulatingmaterial. Electrical current may thus be supplied through the wire 65and contact post IM to the plate 4I, for passage through the block 39and piston 31 to enter the capsule 5@ and thence ow through the pistonI2, block 29 and plate 35 to the terminal post i3 and wire (l5. Usefulheating can thus be produced by the flow of the electrical currentlengthwise in the thin wall of the metal capsule 5G. If the chargeitself is electrically conductive, or if the capsule is omitted, thenthe electrical current would flow entirely or in part endwise throughthe charge itself.

In the latter case, the electrical current required for effectiveheating might be large. In order to avoid danger of overheating themoving piston I2, it is desirable to provide the outer annular retainingmember I8 with an electrical connection through the terminal 48 and wire49, the electrical circuit being completed through the blocks I5, linerI I and contact at 5I with the capsule Sil in its mushroomed state. Boththe wires i5 and 49 may be used in parallel as one side of theelectrical circuit, or either one may be used as a potential lead. Theimportant point is that telescoped at its end adjacent the upper pistonI2 as said piston advances during compression. Likewise, the capsule5I), if used, may also crumple and collapse during application ofpressure. It is feasible, however, to preserve the integrity of theinsulation provided by the sleeve 33 despite such pressure.

As an alternative construction, the tubular liner I I may be insulatedfrom the sector-shaped blocks l5 by insulating the inner face surface at2G (Fig. 1), or inter-surface 32-33 (Fig. 3) by enamel or the like, inwhich case the liner may be heated by heavy electrical current flowlengthwise of the liner after provision of suitable end terminals. Whenusing the liner itself as the electrical heating element, I have foundthat concentration of heat liberation at the center of the bomb can beachieved by reducing the wall thickness of the tubular liner at its midregion. This reduction may take the form of an internal or externalannular groove in the tube wall. In the latter case, the space betweenthe liner and the sector-shaped blocks so formed must be filled withinsulation, or the longitudinal contour of the inner ends of thesector-shaped blocks I5 must be made to correspond to the outer contourof the liner as modined.

If shims of graded thickness are used between the lateral faces of thesector-shaped blocks I5 in order to grade circumferential compression atwill over the faces of the blocks, these same shirns, if made ofelectrical insulating material such as mica flake, could also be made toserve as part of an electrical heating system using the individualsectors as current elements. It is possible to insulate all or desiredparts of the surfaces of each sector so that electrical contact is, oris not made, between the sectors, or between the sectors and the tubularliner, or between the sectors and the outer annular member I8. Manycombinations are thus feasible for heating the liner by electricalcurrent flow in series or multiple, long or short, circumferentialand/or longitudinal paths by suitable contact with part areas of thesectors, to which sectors electrical current is introduced by a suitableelectrical terminal fixed to the sectors. Location of applied heat, inand to the liner, is also of considerable importance and the bombconstruction here disclosed makes for great nexibility and conveniencein achieving the desired heating conditions.

It will, of course, be understood that various details of constructionmay be varied through a wide range without departing from the principlesof this invention, and it is, therefore, not the purpose to limit thepatent granted hereon other- Wise than necessitated by the scope of theappended claims.

` I claim as my invention:

1. In a high pressure apparatus, an outer annular member having atapered inner surface, an inner tubular liner having an outercircumferentially fluted surface, and a plurality of sector-shapedblocks defining an inner surface conforming with the outer surface ofsaid tubular liner and defining an outer surface generally conformingwith the tapered inner surface of said outer annular member, thedimensions of said liner, blocks and annular member being such that uponassembly said blocks are placed under initial radialv compression.

2. High pressure apparatus comprising a relatively thin-walled tubularmember defining a Working volume to be subjected to high pressure, anouter ring-like member concentric with and 1l Y surrounding said tubularmember, and a plurality of sector-shaped blocks in mutual laterallysupporting relationship interposed between said members upon assembly,said blocks collectively having a greater total effective volume thanthat volume lying between said tubular member and said ring-like member,and said blocks being compressed within said outer member upon assemblyto subject said tubular member to an initial inwardly acting radialcompression.

3. High pressure apparatus comprising a relatively thin-walled tubularmember defining a working volume to be subjected to high pressure, anouter ring-like member and a plurality of sector-shaped blocks in mutuallaterally supporting relationship compressively confined betweeny saidmembers to subject said tubular member to initial radial compressionupon assembly f said apparatus, said blocks having longitudinal andradial dimensions at the surfaces of Ycontact with said outer memberthat are both large in comparison with the corresponding dimensions ofsaid working volume, and said blocks in combination normally occupying avolume greater than that occupied by the blocks upon assembly of saidappartus, whereby compression stresses set up in said blocks uponassembly are transmitted directly to said working volume.

4. High pressure apparatus comprising a relatively thin-walled tubularmember defining a working volume to be subjected to high pressure andformed of material that is plastically deformable under the pressures towhich it may be subjected and an outer ring-like member and a pluralityof sector-shaped blocks formed of a material relatively harder than saidplastically deformable material and arranged in mutual laterallysupporting relationship compressively confined between said members tosubject said tubular member to` initial radial compressi-on uponassembly of said apparatus.

5. High pressure apparatus comprising a relativelyY thin-walled tubularmember having -an outer circumferentially fluted surface and an innercylindrical surface defining a working volume to be subjected to highpressure, an outer ring-like member and a plurality of sectorshapedblocks in mutual laterally supporting relationship compressivelyconfined between said members and having surfaces conforming to and incontact with said fluted surface and the inner surface of said ring-likemember to subject said tubular member to initial radial compression uponassembly of said apparatus.

6. High pressure apparatus comprising an outer annular member having aninner tapered surface, an open-ended inner tubular liner providingcacylindrical inner working surface, a plurality of ysector-shaped blocksproviding when assembled an outer tapered surface for `pressure contactwith said inner tapered surface and an inner surface in conformingcontact with said tubular liner and inwardly tapered end recessescoaxial with said inner working surface, said blocks serving to transmitradial compression forces created upon assembly of the apparatus to`said tubular liner, and relatively movable rams having pistons forinsertion into the open ends of said liner and having tapered end facesfor insertion into said tapered end recesses, said pistons having endportions lapped within said cylindrical inner working surface.

7. High pressure apparatus comprising an outer Yannular member having aninner tapeljl.

12 n surface, an open-ended inner tubular liner providing a cylindricalinner working surface, aplurality of sector-shaped blocks providing whenassembled an outer tapered surface for pressure contact with said innertapered surface and an inner surface in conforming contact with saidtubular liner and inwardly tapered end recesses `coaxial with said innerworking surface and in surface contact with said liner, and relativelymovable rams having pistons for insertion into the open ends of saidliner and having tapered end faces for insertion into said tapered endrecesses, said pistons having end portions lapped within saidcylindrical inner working surface and having end seals of plasticsealing material.

8. In a high pressure apparatus having a pair of opposedforce-generating elements, a charge confining and retaining structurecomprising sector-shaped blocks defining when assembled a central cavityfor receiving said elements and having a tapered outer surface, and anannular member for enclosing said assembled blocks and having asimilarly tapered inner surface for cooperation with said assembledblocks to hold the same under radially inwardly directed initialcompression upon assembly of said member about said blocks, saidcompression being transmitted directly through said assembled blocks tothe area lying between said elements.

9. High pressure apparatus comprising an outer annular member, anopen-ended inner tubular member, relatively movable piston elementsvextending into and closing the open ends of said tubular member todefine a high pressure working chamber, and sector-shaped blocksconfined between said outer annular member and said inner tubularmember, said blocks presenting lateral surfaces of initially curvedcontour to es-ftablish a predetermined circumferential Stress throughoutsaid sector-shaped blocks when said. outer annular member is inassembled'position confining said sector-shaped blocks.

10. High pressure apparatus comprising an outer annular member, anopen-ended inner tubular member, relatively movable piston ele-V mentsextending into and closing the open ends of vsaid tubular member todefine a high pressure working chamber, sector-shaped blocks confinedbetween said outer annular member and said inner tubular member, andshims between the lateral faces of said blocks to establish apredetermined circumferential stress throughout said sector-shapedblocks when said outer annular member is in assembled position confiningsaid sector-shaped blocks.

, 11. High pressure apparatus comprising an outer annular member, anopen-ended inner tubular member, relatively movable piston elementsextending into and closing the open ends of said tubular member todefine a high pressure working chamber, and sector-shaped blocksconfined between said outer annular member and said inner tubularmember,said blocks presenting lateral surfaces of initially convexcontour to establish. a predetermined circumferential stress throughoutsaid sector-shaped blocks when said outer annular member is in assembledposition confining said sector-shaped blocks.

12. High pressure apparatus comprising anV outer annular member havingan inner generally conical surface, an open-ended inner tubularA member,relatively movable piston elements Vex REFERENCES CITED The followingreferences are of record in the le of this patent:

Number 14 UNITED STATES PATENTS Name Date Rubin Dec. 1, 1885 ButtlesDec. '7, 1926 Graham July 12, 1938 Ernst et al. Feb. 18, 1941 WackerFeb. l0, 1942 Tooker Sept. 28, 1943 Wacker July 15, 1947 Renier Aug. 31,1948 Hubbert et al. Sept. 20, 1949 Rubber Age, November 1942, pagesOTHER REFERENCES 133 and

